Pencil sharpener



Dec. 7 1926. 1,609,538

C. B. cRoNAN PENCIL SHARPENER Original Filed NOV, 9. 1922 3 Sheets sheetl 11 4 1 TT N irnmw.n

Cl'onazv,

37 m7, mmm@ Dec. 7 1926.

C. B. CRONAN PENCIL SHARPENER original Filed Nov. 9, i922 5 Sheets-Sheet2 gwvwntoz a. Cronaf.

WT-fh, @1mm-Wg Dc. 7,1926. d a 1,609,538

' C. B. CRCNAN PENCIL SHARPENER riginal Filed Nov. 9, 1922 3Sheets-sheet Carre/e l gmntoz |50 chuck, and

Patented Dec. 7, 1926i.

Qumran srarss 1,609,538 Param OFFICE.

CLIFFORD B. CRONAN, OF SHELBURNE FALLS, MASSACHUSETTS.

PENCIL SHARPENER.

Application filed November 9, 1922, Serial No. 599,893. VRenewed.. April17,'1926.

My invention relates to pencil sharpeners andfmore particularly to,mechanically operated pencil Sharpeners employing a rotary cutter forsharpening and pointing pencils.

@ne object ot my invention is to provide an improved cutter device whichshall be adapted to generate a pencil point having a desired contour andthis object is accomplished by causing the cutter to move in apredetermined manner to produce the'kdesired contour orn pencil point.

Another object of my invention is to pro vide an improved chuckmechanism for supporting and automatically shifting the position of apencil relative to the cutter durk ing the sharpcnino' operation, sothat any desired length Ioit Vpoint may be produced on the pencil.

Other objects of the invention will be ap parent from the novelconstruction and arrangement of parts, as shown in the followingspeciiication and as specifically set forth in the appended claims. y Y

rThe invention is'illustrated in the accompanying dra-wings, in whichFigure 1 is a iront elevation or" my im proved pencil Sharpener;

Fig. 2 is a side elevation of the same;

Fig. 3 is atransverse section on the line 8 3 of Fig. 1;

Fig. 4 is a rear elevation; Y

Fig. 5k is a plan view with the casing in horizontal section;

Fig. 6 is a. detail front elevation with the 'chuck removed and thechuck casing insection;

Fig. 7 is alongitudinai section of the I Fig. 8 is a diagramillustrating the principlesY upon which the device operates.

In carrying out my invention, l employ a pedestal 1 which may be of anyconvenient t'orm and may be Vs-ecured in an uprightposition upon atable, as shown in Figs. 1, 2, 3 Vand 4, or may be secured to a sidewall or other ixed support, as indicated by the dotted lines in Fig. 4.Upon the said pedestal, I mount a casing consisting of mating members 2and 3 which are fastened together by stud screws or bolts 4- which maybe placed at convenient intervals. l This'casing is secured to thepedestal by a stud bolt 5 inserted transversely through the upper end ofthe pedestal so that the casing may be supported in an upright positionwhether ,the pedestal be secured upon a table or upon a wall. The casingis of a general circular forml and its top portion consists of a transparent member 6 which may be of Celluloid or other material carried inasubstantially semi-circular trame 7 which is secured to the casingmembers 2 and 8 by suitable screws 8, as will be readily understood. Thespace Abetween the lower portions of the casing members 2 and 3 is leftopen, as shown clearly in Fig. 3, to permit discharge of the chips andparticles of lead, and-in the outer surfaces of the casing members Iform grooves 9 in which/are slidably engaged the lips lor anges l() atthe upper edges of a chip receptacle 11 which may beV of any convenientform and 1s equipped with a transparent member 12 in on-e side so thatthe user may be informed as to when the receptacle is full and should beemptied.

Upon the outer side of th-e casing member 8 is formed or secured a bossorv cylindricalchamber 13, and a spindle 14 is ro` tatably iitted in theouter end Wall of this boss or chamber and in the casing member 2, thespindle being formed with an annular shoulder 15 and being equipped witha stop Vcollar 16 at opposite sides of the wall of the frontcasingmember 2 whereby endwise movement of the spindle is prevented. Up-Y on the rear end of the spindle is secured a crank 17 or otherconvenient form of handle `groove 19 in its outer circumferentialsurface andprovided in its bore with a longitudinal 'groove 2O .which isengaged by a stud lor pin 2l on the spindle whereby the rotation of thespindle is imparted'to the drum and the drum is permitted endwisemovement along the spindle. rlhe cutter or knife 22 is secured to thefrontend of the drum in any convenient manner and, of course, partakesof the motion of the drum, beingrotated with the spindle 14 and alsomoving along the same rearwardly as a cut is made and then returning toits initial position during the succeeding portion of the rotation. Y

Through the front casing member 2 is formed an opening 28 to admit theend of a pencil 24, and upon the out/er .side of the said casing memberis formed a Achuck casing 25 which supports a chuck 27 for resilientlygripping the pencil and holding the samev in an oblique positionrelativeto the Fil cutter blade. Aruis chuck is illustrated as acylindrical tube in which is secured a sleeve member 2S provided withresilient` inner portions Q9 contracted so as to be spaced troni thewall ot the tubo 2T in ord r to provide a greater range ot grippingaction on the pencil. rlhe sleeve is shown as composer ot resilientmembers arranged to extend longitudinally ot the pencil, but it isobvious that the sleeves QS may he provided with spiral members adaptedto encircle and grip the pencil. lllhichever form ot sleeve is employed,it may be desirable to aid the gripping action on the pencil supportedtherein by means ot' a spring 30 coiled around the resilient membersassociated therewith, as shown in Fig. T. The inner end ot the splitspring slcerc is flared as indicated by the immoral 3l, therebyproviding retaining means tor the spring 30.

Fixed upon the outer circumference ot the chuck is a helical gear 82which meshes with a helical gear or worm 83 mounted in any convenient.manner so as to rotate the chuck tube 2T, as vill be readilyunderstood. As shown most clearly in Fie'. E., the gear 32 abuts theouter end of the chuck casing which provides a thrust bearing it'or saidgear and the chuck in one direction. rlhe chuck cover and gear casing 2Gis secured upon the casing ano is properly loi-mcd -to (it around theend oft' the chuck and ot the chuck casing and enclose the gearing bywhich the chuck is rotated. lt will be readily noted that the chuckcover and gear casing is constructed with an internal annular shoulderwhich forms a thrust bearing at the outer side oit the gear so that end-Wise movement oit the chuck is prevented.

rllhe helical gear-,33 is termed integral with or hired rigidly toconcentric Geneva stop wheel 3l vhioh is adapted to be periodicallyengaged and actuated by a pin carried by the stop collar 1G which issecured upon the front end ot the spindle le. rlhe cani groove 19 isengaged by a roller 3G mounted upon the inner end oit a stud 37 which isscrewed tlnough one wall oit the oltset or chamber 13, as shown. It willthus be readily seen that, as the spindle 1ais rotated, the cutter iscaused to also rotate about the said spindle as a center and through theengagement of the cam groove 19 with the roller 3G, the drum and thecutter are caused to move rearwardly along the spindle. By rotating thecutter the stop collar 1G is also rotated and, through a portiony ot therotation, the pin on said stop collar engages and actuates the Genevastop wheel 3ft and a partial rotation is thereby imparted to the gears33 and 32 so that the chuck is rotated one step and the pencil likewiserotated about its own axis to present a it'resh surface to thc cutter.It will, oit' course, be und rstood that, the cutter operates upon thepencil during a portion of its revolution, and during the remainingportion ol its revolution is returning to its initial position, and thepencil is rotated during the return movement ot the cutter.

l'llithin the casing, a stop or rest 38 is secured upon the trontwall otthe same and in alinement with the chuck 2.7 and the opening 23 in thecasing so that the end of the pencil may be resiliently supportedagainst the thrust ot the cutter and the insertion ot the pencil may beproperly limited. Ellis stop may conveniently be a resilient sheet metalbracket having a cuplikc member 23) presented to the opening 23 andhaving a conical portion ai() extending axially troni the cup-likeportion. When a new pencil is to be sharpened, it is inserted throughthe chuck so thatits end bears against and rests in the cup-like portion39 ol? the stop rest. yhe cutter is then operated so as to cutcompletely around the pencil und a blunt point will be thereby termed. lit be then deg-,aired to produce a long tapering point ot lead, thepencil is further inserted so that the extreme point thereof will restin the conical grooved portion @LO ot the rest, and the sharpeningoperation is repeated.

.fits shown and as will be readily understood, the chuck is disposedobliquely to the cutter so that the pencil to be sharpened e1;-

uids across the plane ot the cutter, and in S l have illustrateddiagrannnatically mathcn 'ical considerations upon which fuccessiuloperation of the invention is fr cutting edge o' symmetricalmathematical term is rotated about an axis so as to cut a chip trom theend of the iencil. 'lfhe desir cutting results may be obtained eith r bygiving the cutter a combined rotary a id axial nnrvement or by proridinga spacially formed or warped cutter adapted to combine beth the radialand axial components necessary to generate the same contour when rotatedabout the proper axis.

'lhc :torni oit cutter which l have chosen lor illustration issemi-circular cutter hava center C mounted to rotate about an eccentricaxis @u rluis torni oit blade is an easy one to produce and grind andpossesses satisfactory cutting properties. rl"he plan shows the axis otthe pencil inclined at an angle fr to 'the plane ot the cutter blade andalso at certaii distance above the axis of the rotation olf the cutter(see elevation). rEllis anglo is adjusted in relation to the arelc 'oittaper ot the pencil point to give factory-5 clearance to the cuttingedge and have a smooth operation. "n the elevationn one hundred andeighty degrees ot' rotation are spaced olif every ten degrees, and

radial lines. projecting trom the center ot rotation, tor these equalangles intersect the periphery ot the cutter blade and divide the itinto arcs of varying length. angle'ofthirty degrees gives the necessaryclearance for the cutter before it comes in contact with the wood of thepencil and starts to cut. As the cutter continues through successiveequal angles of rotation, each are of the cutting edge passes throughthe plane yof the pencil at a constantly increasing distance in radialdirection from the center of rotation. In cutting, the advance of thecutter in the plane of the pencil and in the direction of the pencilpoint is gradually increased to a maximum and then gradually decreasedto a minimum as the end of the pencil is reached. It may thus be statedthat the angle of cut caused by the radial and axial advance of thecutting edge alongv the pencil varies gradually andthe consecutive arcsare practically parallel through the largest portion of its radius ofaction, thus insuring a smooth cutting action. By thus producingdifferent proportions of varying radial and axial advance of the cutterduring each revolution thereof, the cutter'may be caused to move so asto produce any desired symmetrical point on the pencil. The plan in thediagram shows how each unit of radial advance of the cutter must becombined with the proper amount'of axial advance to generate anypredetermined contour for the pencil point, this motion beingsynchronized by the action of the cam drum.

. Normally, the cutter produces a point of circular cross section, thepencil being automatically shifted about its own axis through the actionof the Geneva stop wheel and the parts associated therewith, ashereinbefore set forth. If it be desired to produce a chisel point, thepencil is insertedY in the usual manner and one complete cut is made.The pencil is then withdrawn and manually rotated about its own axisthrough an angle of one hundred and eighty ydegrees and then re-insertedin the chuck and the cutter operated to make another complete cut. Thisprocess obviously acts upon diametrically opposite portions of thepencil so that a chisel-like .point of lead is produced. Y

lVhen a new pencil is to be sharpened, it is inserted through the chuckin the usual manner and its end will abut the cup-like portion 39 of thestop rest. The cutter is then operated in the usual manner, and as aresult of the operation will reduce the end of the pencil so as to forma blunt point. This operation may be all that is needed to sharpencrayons or similar marking elements. If, however, it be desired toproduce a sharp lead point, the pencil is pushed further throughtherchuck after the blunt point has been formed, so that its reducedextremity rests in the tapered conical portion of the stop rest, andfurther operation The first of the cutter then produces the desiredpoint upon the lead. It will be readily noted that the pencil `is firmlysupported in the chuck so that it will properly resist the thrust imposed by the action of the cutter but at the same time there issufficient yielding to prevent breaking of the lea-d or excessive strainupon the cutter. It will be readily noted that the shaving action of thecutter is in the direction of the grain of the wood of the pencil andnot across the grain, thereby producingk a smooth surface and having theleast tendency to break the lead. 4The reduction of the tendency tocause breakage is aided by the peculiar shearing cut taken, the ratio ofthe length yof cutting edge coming into contact with the Vwork to theamount of advance in the direction Vof the point being adjusted tosecure free lcutting action. It will b e noted that the cutter starts toremove a chip as it rotates about its axis and comes into contact withthe outside of the pencil, the chip being removed from heel to point bythe continued rotation of the cutter `combined with an axial motion. Myimproved pencil Sharpener is'simple, compact, easily operated, may beproduced at a low cost and will be found uniformly eiiicient in use.

Having thus described the invention, what is claimed as new is: Y Y

1.'A pencil Sharpener including a cutter having a symmetrical cuttingedge and mounted for eccentric rotation, means for rotating the cutterand for moving it along the axis of its rotation, andV means forsupporting apencil across the path of travel of the cutter and obliquelyto the same.

2. A pencil Sharpener including a cutter having a semi-circular cuttingedge, Ameans for rotating the cutter about an eccentric axis, means foreffecting movement of the cutter along its axis of rotationV `during itsrotary movement, and means for supporting a pencil obliquely across theplane of the cutter.

3. A -pencil Sharpener including a cutter having a symmetrical cuttingedge and mounted for rotation about an axis eccentric to said edge, adrum to which the cutteris secured and disposed concentric with the axisof rotation of the same, said drumhaving a longitudinal groove extendingthrough its bore, means for eifecting endwise movement of the drum, aspindle extending through the bore of the drum, a fixed member on thespindle engaging the groove in the drum, means for rotating the spindle,and means for supporting a pencil obliquely across the plane of thecutter.

4. A pencil Sharpenerr including a tubular chuck'to receive and hold apencil, a stop rest spaced from and alined axially with the chuck, acutter disposed in a palne atan oblique angle to the axis ofthe chuckand intersecting said axis between-the chuck and tlie'stopv reet,audmeans for sin'iiiltaneously rotating; theV cutter` and positivelymoving` the-same along its axis of rotation.

5; A pencil:Sharpener incliidinga tubular chuck, a stoprest spaced ltromandfalined axially Witlrthe chuck` and having, a cupped portionpresented tothe cliuekandaltapered conicall portion, extending axiallyfrom the cupped portioma cutter disposed: in a. plane at` an obliqueanglo to the axis of the chuck and! the said stop rest, and means forrotatingi'said cutter andinoving it along its axis of rotation:v

6: A peneilr Sharpener including a` chuck consisting: ot a= tube,A alongitudinally split spiingsleeve sccuredat one end inthe outer end ot'the tube and adapted to t closely around a pencill inserted through thetube, the ends. oit the tube beiugliared, a spring coiled=` aroundl saidsleeve between' the saine and the tube and having its ends bearingagainst the 'flared ends ot the sleeve, a cutter disposedlatwan` obliqueangle to the axis of the` chuck,Y and means for simultaneously rotating;the cutter. and moving it bodily aloiigits axis of. rotation.

7. A pencil sliarpener including a chuck constructed to receive andsupport a pencil to be sharpened7 a cutter mounted atf an oblique angleto the axis ot the chuck, means for rotating the cutter andsimultaneouslyinovingit endivise along its axis oit" rotatioii tronrandtoward the pencil, and

means 'for partially rotatingthe chuck and` theV pencil therein during.the endivise movement: oitV the cutter towardi the pencil;

8. A pencil shaiupener iiicliidinga spindle, ai cutter mounted on thespindle to rotate i therewith and inove bodily along the saine duringits rotation, a chuck. disposed at an oblique angle to the plane of thecutter, a4

Greneva stop `Wheel disposed adjacent the chuck, gearing operativelyconnecting the T ehucln with. said stop Wheel, and gearing' operativelyconnecting the Gfeneva` stop Wheel with the spindle whereby the chuckwill have alternate intervals of restY and movement during.` rotationot' the spindle.

9. A pencilV Sharpener comprising means for holding a pencil to hesharpened, a rotary cutter arranged to` cut the pencil obliquely to, itsaxis and move longitudinally7 thereof, and means' for varyingthe angleoff cut during the longitudinal movement of..

the cutter along the axis of said pencil.,

l0. it pencil.v Sharpener comprising means tor holding ay pencil to besharpened,A a` rotary cutter arranged to cut the pencilv obliquelytoitsfaxis andinove longitudinally thereof, and means i'forprogressively7 diminishing the angle ot eut` during the` longitudinalmovement ol' the cutter along the axis oit saidpencil.

1l; Jr. pencil sharpener comprising a chuck tor. holding a pencil to besharpened, an. -inate cutter blade mounted tor eccentric rotation, meansfor rotating; the cutter andy advancing the cutter edgeooliquely totheaxis ol the pencil, whereby the angle'otl thev cut caused by the cutteredgevaries-rom a` niaz-iininii to a iiiiniinuni during each'rotafl tionof the cutter.

l2. n. pencil sliarpener comprising meansr 'for holding. a pencil to besharpened, a rotary cutter blademind; ieana for rotatingl the cutter andsimultaneouslyv moving; said cutter along` its axis ofirotation,\vhereby the angle or' the cut caused by the cutteigvariesAt'ronria maximum to aniinimuni duringeach rctationoit the cutter.

lil. The method of sharpening a pencil, which comprises advancingacutter oblique-Y lj.' to the r s ot the pencil and longitudi* nailj.'the angle ot cut durinoztlie longitudinal adiI vancenient of the cutterto the axis of the pencil.y

la. The method of sharpening a pencihwhich comp` ly to the axis of thepenciland longitudinally thereof and varying thev angle off cutf duringthe loi'igitui'linal advancement of the cutter to the axis the pencil;

l5; fr pencil Sharpener comprisinga drinn having a cani groove initscircumferential surface, a lixed stud engaging. said cam` groove, meansVfor rotating. theV drinnA andi peri'nitting,endivisemovement oit' thesaine during its rotatioina cutter secured to thev toi vai-d end oit thedrinn andinounted:eccentric to the axis thereof, andmeans1 l'orsupporting a pencil obliquely across the plane ot the cutter.

ln testimony whereof lfaftixA my signature.v

CLFFORD B CRGNAN. [n s] lises advancing acutter oblique

